As a user interface of an information device, devices exist that display screens including a plurality of screen layers. Each screen layer retains information representing transmittance called an alpha value for a region on the screen layer. By displaying each screen layer in a superimposed manner on the basis of the alpha value, it is possible to display a lower screen layer only in a specified region, and when screen layers overlap each other, it is possible to perform display such that translucent images overlap each other.
In such a device, there is a possibility that a user selects a specific object by clicking a mouse, tapping a touch panel, or the like on a screen on which a plurality of screen layers are displayed. At this time, an event indicating that there has been input from the user is generally sent only to a foremost screen layer. However, since the object the user is trying to select is not necessarily displayed on the foremost screen layer, there arises a problem that the user cannot immediately select the object the user wants to select.
As a method for solving this problem, for example, in Patent Document 1, a method is disclosed for setting a threshold for each screen layer, receiving a user input event when the alpha value at coordinates at which to receive the input from the user exceeds the threshold, and delivering the user input event to a lower screen layer again when the alpha value at the coordinates is less than the threshold.
In addition, for example, in Patent Document 2, a method is disclosed under which priority of each screen layer is set in advance for a type of user input event, and a delivery destination of the user input event is decided in accordance with the type of the user input event and the priority.